Underreamer blade check



1,480,357 R. A. WILSON Filed Aug. 14. 1922 U .W%\II-II| W In? 7 l w A i 11 P UNDERREAMER BLADE CHECK mm \\\\\\\\\\\\\\\\$%M MM/\T Jan. 8, 1924.

Patented Jan. 8, 1924-.

' ROBERT A. WILSON, or DALLAS, TEXAS.

UNDERR-EAMER BLADE CHECK.

'Application filed August .14,; 192,2. Serial No. .5s1,e4a.

Tola'Zl whom it may concern:

Be it known that I RO ERT A. WI SON, a citizen of the United states, residing at Dallas, in the county of Dallas and State of Texas, have invented certain new and useful Improvements in Underreamer Blade Checks, of which the fiollowing is a specification.

This invention ha relation to new and useful improvements in checking devicesfor underreamers. f

In those types of underreamers where the blades are expanded by the action of a coiled sprimgwunder compression or by other means considerable unnecessary wear is occasioned upon the upward stroke or movement of the underrea-mer. Thi is particularly present in mud and other format-ionssin which the blades have a tendency to stick Inlsuoh instances the blades will beheld by the earth, while the body of the underreamer' will move upwardly, thus compressingthe spring until the tension of thesaidspring evercomes the retardationof the blades. When this ;occurs the blades will be'sud-denly released and will be drawn into their seats un+ :der :the influence of the spring with considerable force, whereby an unnecessary shock and wearing impact results. Further this condition causes an unnecessary wear ion-all of the working parts. The obi-est .of the inventioni to overcome this objection by providing means for preventing a relatively quick or suldden movement of the body With relation to the blades when the under-reamer is moved upwardly.

A further object is to provide means for permitting a comparatively quick expansion of the spring and extension of the blades.

when the underreamer is lowered to the bottom of the well, vlout o-fiering such resistance as to prevent retardation of the blades upon an upward m vement of the-body of the 'underreamel', where such movement is during the reaming operation; however being arranged :to permit a gradual retraction of the blades under asteady upward pull, when it is-desired to remove the underreamer from the well; r

A still further object oft/he invention is to provide means within the underreamer tor resisting-a quick or suddenmovem'ent of the body with relation to the blades and also for prevenfiinga'sudden compression of the spring which holds :the blades expanded.

Another object is to cushion the expans-lon action of the blades so that when they are released the spring will not act with a shock. s A construction designed to carry out the invention together with other features will be hereinafter .more particularly pointed out.

The invention will be more readily understood from a reading of the following specification and by reference to accompanying drawings, wherein: Fig. 1 is an elevation of an underreamer constructed in accordance with my invena Fig. 2 is an enlarged JZragment-a-ry verti bore of the body pivot-ally support the blades at its lower-rend and has a collar 15 resting upon a-spring 16 coiled around said mandrel.

When the mandrel is moved downwardly relatively of the body Hthe spring is compressed and the blades are retracted. The construction described is typical and the invention is not to be limited thereto. V

At the upper end otthe mandrel I provide a head 18 having a vertical diametrical slot 19 normally having its lower end in registration with the upper'ends of slots 20 in the body 10. By inserting the usual wedge (not shown) in the slots and engaging the same with the bottom of the slot 19 the head and mandrel may be depressed to set the blades. v

A tubular section 21 having a central bore or chamber 22 and of suhstantia-l-lythe same mean diameter as the body, has its lower end screwed intothe upper end of the body. A suitably constructed stuffing box; 23 is screwed into the lower end of the section 21 and a. plunger rod 24 passes thru thesaane into the chamber '22. The rod is integral with the upper end of the head and is moved thereby. 7 7

The upper end of the rod screws into a piston head '25. .Apiston comprisinga pair of disks 26 between which :a pair-01f flexible cups 2?? are confined, lS IIlOltIttQCl on the rod valve.

between a collar 28 and'the lower end of the head. A port 29 in the rod below the piston communicates with an axial passage 30 extending to the upper end of the rod and opening into cavity 31 in the head. The chamber 22 contains a liquid,

piston or quick relative upward movement of the body. I

In the upper end of the cavity is formed an inverted valve seat 33in which a valve 34- is received. The valve has a steam 35 pass- 7 ing thru the top of the head and is supported by a tension spring 36 which acts to seat the Immediately above the valve a recess 37 is provided and radial ports 38 extend from the recess thru the head. .The ports 38 have a much larger area than the ports 32 and when the valve is unseated, these ports 38 will permit a comparatively rapid. passage of the liquid and thus not interfere with upward movement or the iston.

Then the mandrel 14 is forced downwardly by the wedge the head 18 and rod will be moved downwardly thus carrying the piston to the bottom of the chamber. During this movement the liquid will pass thru the port 29, passage 30, cavity 31 and the ports 32 into the chamber 22 above the piston. The

downward movement of the parts will be slow on account of the size of the ports When the underreamer blades reach the bottom of the casing and pass below the same the spring 16 which has been compressed will be released and the blades 12 expanded. This Wlll move the piston upwardly in the chamber 22. The liquid in the chamber above the piston will pass thru the ports 38 and recess S'T and unseat the valve 34 50 that a free passage thru the passage30 and port 29 is had and the piston permitted to move upwardlywvith substantially little resistance. However, suhicient resistance will be offered to cushion the ex panding of the blades and preventthe usual impact dueto the sudden release of the spring.

7 When the blades are fully expanded and seated the piston will be at the upper end of the chamber. as is shown in Fig. 2 and a solid body of liquid will be below the piston ottering resistance to its downward movement. When the body and section 21 are moved upwardly on the upward stroke of the underreamer the blades cannot stick or be retarded because the liquid below the piston prevents any movement of the body relatively of the blades and mandrel and also eliminates compression of the spring.

By this arrangement play of the blades and mandrel is obviated and the wear incidental to the usual relative movement during the underrea'ming operation is removed. This will not only prolong the life of the tool, but will increase its efficiency and tend to eliminate churning in the hole. It is obvious that a steady upward pull on the parts 10 and 21 will cause the liquid to flow thru the ports 32 when the blades are engaged with the bottom edge oi the casing thus the blades may be collapsed.

Various changes in. the size and shape of the various partsas' well as modifications and alterations may be ;made within the scopeot' the appended claims.

What I claim, is: r r

1. In an underreamer blade check the combination with a body structure and a relatively moveable mandrel and cutting.

sudden relative upward movement'ofithe body-structure independently of the blades when the underreamer is moved thru its upward stroke.

3. In an underreamer blade check,.the combination with a body structure and spring supported blades moveable' relatively of the body, of means for checking a sudden compression of the spring] a 4:. In an underreamer blade check, the

' combination 'with a. body structure and spring supported blades movable relatively of the body, of means for checking a sudden compression of the spring and arranged to permit a quick expansion of the spring.

7 5. In an underreamer blade check; the combination with a body structure and a movable mandrel carrying expanding blades, of a check chamber in the body-structure containing-a body of liquid, and a piston mountedin the chamber connected with the mandrel and sustained by the liquid against a sudden relative upward movement of the body structure.

6. In an underreamer blade cheeky the I combination with a body structure and a movable mandrel carrying expanding blades, of a. check chamber in thebodystructure containing a body of liquid,and a piston mounted in thechamber connected with the mandrel and sustained by the liquid against a sudden relative upward movement I of the body structure, the piston having passages for permitting a restricted flow of the liquid for allowing a gradual upwardmovement of the body structure relatively of the mandrel and blades.

7. In an underreamer blade check, the

combination with a body structure and a' movable mandrel carrying expanding blades, of a check chamber in the body structure containing a body of liquid, and a piston mounted in the chamber connected with the mandrel and sustained by the liquid against a sudden relative upward movement of the body structure, the piston having passages for permitting a restricted flow of the liquid for allowing a gradual upward movement of the body structure relatively of the mandrel and blades, the piston also having means for permitting a quick upward movement relatively of the body structure for expanding theblades. V a 8. In an underreamer blade check, the combination with a body structure and a movable mandrel carrying blades, of a liquid containing chamber carried by the body structure, a head mounted on the mandrel, a plunger rod carried by the head and ex-. tending into the chamber, a piston mounted on the rod and having restricted passages for the flow of the liquid in one direction, and a self-closing valve permitting flow of the liquid in the opposite direction.

In testimony whereof I afiix my signature.

ROBERT A. WILSON. 

